The subject matter disclosed herein relates to power transmission systems and, more particularly, to systems for analyzing and/or responding to faults in a power transmission system.
Power transmission systems are generally used to transmit power from generation plants to a set of power consumption locations (e.g., homes, commercial buildings, businesses, etc.). These power transmission systems include a variety of components (e.g., transmission lines, high voltage transmission lines, extra high voltage transmission lines, ultra high voltage transmission lines, cables, transformers, conductors, etc.), which are used to convey power over the distances between the generation plants and the power consumption locations. Some power transmission systems employ a three phase system which may require less conductor material to transmit electric power as compared to single-phase, double-phase, or direct-current systems at the same voltage. During operation, faults may develop within the three phase system as a result of any number of conditions (e.g., a tree falling on a component, a lightning strike, a bird shorting a component, etc.), leading to arcing events and/or disruptions of service. These faults may be transient (e.g., self-extinguishing) or permanent (e.g., requiring technician assistance to correct the fault), and may be single phase, double phase or triple phase.
In these three phase systems, transient faults are the most common form of fault. The short circuit arc of a transient fault is usually self-extinguishing after the opening of a set of line circuit breakers. Thus, some power transmission systems include protection relays using fixed time interval reclosure methods to automatically detect and treat transient faults within the system. In response to a detected fault, these systems open line circuit breakers for the phase(s) which is faulted, and these circuit breakers remain open for a predetermined time period so that the arc extinguishes. After the fixed time interval has passed, the line circuit breakers are reclosed and flow of service is restored. However, in some cases, the pre-set time interval may be longer than necessary to extinguish the arc, resulting in a longer than necessary interruption of service. In yet some other cases, the selected time interval may not be long enough to fully deionize the fault path and, when the line circuit breakers are reclosed, the arc restrikes. Thus, the use of these fixed time interval systems may lead to inefficient operation, arc restriking, system stress, improper power outages, and equipment damage.